S. William Zito

α-Glucosidase inhibitory activity of Syzygium cumini (Linn.) Skeels seed kernel in vitro and in Goto–Kakizaki (GK) rats

Syzygium cumini seed kernel extracts were evaluated for the inhibition of alpha-glucosidase from mammalian (rat intestine), bacterial (Bacillus stearothermophilus), and yeast (Saccharomyces cerevisiae, bakers yeast). In vitro studies using the mammalian alpha-glucosidase from rat intestine showed the extracts to be more effective in inhibiting maltase when compared to the acarbose control. Since acarbose is inactive against both the bacterial and the yeast enzymes, the extracts were compared to 1-deoxynojirimycin. We found all extracts to be more potent against alpha-glucosidase derived from B. stearothermophilus than that against the enzymes from either bakers yeast or rat intestine. In an in vivo study using Goto-Kakizaki (GK) rats, the acetone extract was found to be a potent inhibitor of alpha-glucosidase hydrolysis of maltose when compared to untreated control animals. Therefore, these results point to the inhibition of alpha-glucosidase as a possible mechanism by which this herb acts as an anti-diabetic agent.

Development and validation of a gas chromatographic-mass spectrometric method for simultaneous identification and quantification of marker compounds including bilobalide, ginkgolides and flavonoids in Ginkgo biloba L. extract and pharmaceutical preparations.

A gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the simultaneous determination of seven major chemical markers (bilobalide, ginkgolides A, B, C, kaempferol, quercetin and isorhamnetin) in phytopharmaceuticals of Ginkgo biloba L. The intra-day relative standard deviations (RSD) and inter-day RSDs were based on the analysis of the standardized Ginkgo biloba L. extract on the same day and on the following 3 consecutive days. The intra-day RSDs ranged from 1.21% (bilobalide) to 6.20% (kaempferol). The inter-day RSDs ranged from 2.10% (bilobalide) to 10.42% (isorhamnetin). Mean recoveries ranged from a low of 63.0 +/- 5.3% (isorhamnetin) to a maximum of 103.5 +/- 6.0% (ginkgolide A). Calibration curves were linear in ranges between 2.73 and 36.36 microg/ml for the markers. Limits of detection ranged from a low of 0.5 microg/ml (bilobalide) to a high of 2.5 microg/ml (quercetin). The limits of quantitation were a low of 1.1 microg/ml (gingkolides A, B, C) to a high of 7.5 microg/ml (kaempferol). The method was applied to a standard extract (>6% total terpenoids and >24% total flavonoids) and six ginkgo capsule phytopharmaceuticals.

The combined use of DSC and TGA for the thermal analysis of atenolol tablets

The New York Regional Laboratorys forensic pharmaceutical group used thermal analysis (TA) to ensure adherence to batch formulations by drug manufacturers. TA in our laboratory consisted of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC and TGA were used to analyse finished dosage forms and their components. In this study the components of atenolol formulations were qualitatively identified by analysing individual components and comparing with the finished product. DSC and TGA were used together to develop a profile of batch formulations, with each analytical technique giving complementary types of information. For example, the excipient sodium starch glycolate was identified by DSC and confirmed by TGA. These experimental results demonstrated the use of TA for the characterization of finished dosage forms and the qualitative identification of some of the individual components in batch formulations.

Isolation and identification of process impurities in trimethoprim drug substance by high-performance liquid chromatography, atmospheric pressure chemical ionization liquid chromatography/mass spectrometry and nuclear magnetic resonance spectroscopy.

Twenty-two lots of recently synthesized trimethoprim drug substance, from five different manufacturers, in three different countries of origin, China, Israel and the United States, were investigated for the presence of impurities. A liquid chromatographic system, using gradient elution, and a mobile phase consisting of 0.25% TEA/0.1% formic acid (pH 5.8)--acetonitrile, was used to separate and detect two significant, recurring impurities in trimethoprim drug substance. The two impurities were isolated by preparative liquid chromatography and identified, using a combination of liquid chromatography/mass spectroscopy and nuclear magnetic resonance, as 2,4-diamino-5-(4-ethoxy-3,5-dimethoxybenzyl) pyrimidine and 2,4-diamino-5-(3-bromo-4,5-dimethoxybenzyl) pyrimidine. These impurities were not detected by the compendial method and were present at significant levels in 17 of the lots tested. Total impurity concentrations were in the range of 0.1-2.1%.

Potentiation of opioid analgesia by cocaine: The role of spinal and supraspinal receptors

These studies examined the effect of cocaine on the analgesia produced by systemically and centrally administered opioid agonists. Cocaine (50 mg/kg, s.c.) increased the analgesic potency of systemic, ICV and IT morphine; and the ICV and IT analgesic effects of the delta selective peptide, [D-Pen2,D-Pen5]enkephalin (DPDPE). Cocaine also increased the analgesic potency of the mu selective ligand [D-Ala2,NMePhe4,Gly-ol5]enkephalin (DAGO) administered ICV. However, cocaine did not alter the ED50 for IT DAGO. GC-MS studies indicated that brain cocaine concentration was approximately 3.0 micrograms/g wet weight 45 min following s.c. administration. These results suggest that cocaine-induced increases in opioid analgesic potency are mediated at brain mu and delta receptors and spinal mu receptors. Furthermore, there might be functional differences between spinal and supraspinal sites at which DAGO produces analgesia.

Constituents of Chrysanthemum cinerariaefolium in leaves, regenerated plantlets and callus.

Abstract Callus, aseptic plantlets and leaves of three-year-old, greenhouse grown Chrysanthemum cinerariaefolium were investigated for pyrethrins and the monoterpenes known to be precursors to them. The callus produced chrysanthemyl alcohol, chrysanthemic acid and chrysanthemum dicarboxylic acid but did not contain detectable amounts of pyrethrins. Leaves from aseptic plantlets and three-year-old plants produced geraniol, chrysanthemyl alcohol, chrysanthemic acid, chrysanthemum dicarboxylic acid and all six pyrethrins.

Effect of Wrightia tinctoria and Parthenocissus quinquefolia on blood glucose and insulin levels in the Zucker diabetic rat model.

The aim of this study is to evaluate the antidiabetic activity of two Indian Ayurvedic herbs using an oral glucose tolerance test and blood insulin levels to understand the mechanism of action using the Zucker diabetic rat model. Herbal extracts of Wrightia tinctoria and Parthenocissus quinquefolia at a dose of (250 mg/kg body weight) were used throughout the study. Following a glucose challenge of 2 gm/kg using oral gavage, a timed glucose tolerance test was used to determine the ability of these extracts to alter glucose levels in diabetic animal model. The glucose lowering activities of these extracts were then compared to the controls. Both tested herbal extracts have shown to exhibit significant (P < 0.05) hypoglycemic activity compared to the control. W. tinctoria and P. quinquefolia have an antidiabetic activity which reduced the blood glucose level in oral glucose tolerance test significantly compared with the control. To further understand their mechanism of action, blood insulin levels were also studied using an insulin Elisa assay. These studies revealed that the herbal extract of P. quinquefolia has direct correlation between glucose and insulin levels. However, W. tinctoria significantly lowered blood glucose levels (P< 0.05), while it did not show any correlation between blood glucose and insulin levels. Based on these findings, it can be concluded that hypoglycemic effects of W. tinctoria are more complicated than P. quinquefolia, and may involve other possible mechanism of action.

Structure elucidation and inhibitory effects on human platelet aggregation of chlorogenic acid from Wrightia tinctoria.

Abstract Background: Interest in natural compounds as sources of potentially new treatment options is growing rapidly. Preliminary screening of many different plant extracts showed that Wrightia tinctoria acts as a potent human platelet aggregation inhibitor. The aim of the present study was to isolate and characterize the active compound responsible for potent inhibition of human platelet aggregation in vitro. Methods: A 70% ethanolic extract derived from W. tinctoria seeds was fractionated with chloroform followed by ethyl acetate. The ethyl acetate fraction was further fractionated and purified through a series of three successive column chromatographic separations using silica gel, Sephadex LH‐20, and C‐18 columns. Liquid chromatography coupled to negative electrospray ionization tandem mass spectrometry (LC‐MS/MS) and nuclear magnetic resonance (NMR) studies were performed in the structure determination of the active phenolic compound present in the ethyl acetate fraction of W. tinctoria seeds. Results: A phenolic compound has been isolated and identified as chlorogenic acid by LC‐MS/MS and NMR studies. Chlorogenic acid showed concentration-dependent inhibitory effect on collagen-induced platelet aggregation in vitro with an IC50 of 0.2363 μg/μl. Conclusion: The present data suggest that chlorogenic acid can be developed as potential antiplatelet agent in the treatment of cardiovascular diseases in diabetes mellitus.

Anticancer Activity of Oldenlandia Diffusa & Viola Philippica Car

Abstract: Oldenlandia diffusa (OD, Bai Hua She She Cao) and Viola philippica Car. (VPC, Zi Hua Di Ding) are both commonly used traditional Chinese medicine (TCM). Although studies have demonstrated their anticancer activities on cancer cells both in vitro and in vivo , no systematic reports were carried out. The objective of this study was to examine their cytotoxic activities in vitro. We used the ethanol extracts of these two herbs and examined their cytotoxic effect on four cancer cell lines and two non-cancer cell lines using an MTT cytotoxicity assay. The results showed that the ethanol extracts of OD and VPC effectively inhibited the growth of all the cancer cell lines, particularly MiaPacA-2 cancer cells. Significantly less cytotoxicity was observed in non-cancer cell line NIH3T3. We also tested the drug sensitivity of OD and VPC in a P-glycoprotein (P-gp) overexpressing multidrug resistant cell line KB-C2. Our results showed that OD and VPC can potently inhibit the growth of KB-C2 cells. Therefore, this study has revealed the remarkable anticancer activity of these two TCMs. To the best of our knowledge, this is the first report that shows potential anticancer activity in multidrug resistant cells in extracts of OD and VPC using scientific methods of evaluation.